Randomized crossover trial of amoxapine versus vitamin B12 for retrograde ejaculation

ABSTRACT Objective To compare the efficacy and safety of amoxapine and vitamin B12 for treating retrograde ejaculation (RE). Materials and Methods Between May 2009 and November 2012, this open-label, randomized, crossover study enrolled 26 men suffering with RE at Department of Reproductive Medicine, Omori Hospital. Patients were randomly allocated into two groups (n=13 each). The amoxapine-B12 group received amoxapine (50 mg daily for 4 weeks, orally) followed (after a 1-week washout period) by vitamin B12 (500 μg three-times daily for 4 weeks). The B12-amoxapine group received the opposite regimen. All patients masturbated to ejaculation at least twice during each treatment period. The primary outcome was antegrade ejaculation of semen, as reported by the patient, on more than one occasion during either treatment period (defined as treatment success). Any adverse events were noted. Success rates were compared between treatments using Fisher’s exact test. Results One patient (B12-amoxapine group) withdrew for personal reasons (breakdown of marital relations); all other patients completed the study. Overall success rate was 88% (22/25). Success rate was higher for amoxapine than for vitamin B12 (80%, 20/25 vs 16%, 4/25; P<0.0001). 18 patients were responsive to amoxapine but not to vitamin B12, 2 patients were responsive to vitamin B12 but not amoxapine, 2 patients were responsive to both drugs, and 3 patients had no response to either drug. One patient (4%) reported sleepiness and 2 (8%) reported constipation while receiving amoxapine. No adverse events were reported during vitamin B12 treatment. Conclusions Amoxapine may be an effective, safe and well-tolerated therapy for RE.

Successful management of rectal tenesmus with oral amoxapine and infusional lidocaine in a terminally ill cancer patient：a case report and literature review

Background: Although rectal tenesmus in patients with advanced cancer can have marked negative impact on quality of life, effective treatment has not yet been established. Case: A 71 -year-old man with an inoperable rectal cancer developed tenesmus 11 months after a colostomy. Tenesmus worsened over the following 3 months, and the patient suffered from involuntary straining every 5-15 minutes. After unsuccessful symptom control with radiotherapy to the primary lesion, we started oral amoxapine 25 mg that alleviated symptoms related to tenesmus. As the general condition deteriorated, however, oral intake became difficult. After the discontinuation of amoxapine, the tenesmus recurred even though intravenous administration of clomipramine was initiated. We started continuous infusion of intravenous lidocaine 200 mg/day which successfully relieved tenesmus. The dose of lidocaine was subsequently increased to 290 mg/day for worsening symptoms, which continued to control his distress caused by tenesmus until he died. Consideration/Conclusion: This is the first report that demonstrates the efficacy of oral amoxapine for rectal tenesmus with malignant tumor. After the discontinuation of amoxapine due to the inability of taking medications orally, symptoms remained under adequate control with infusional lidocaine until the patient died. Further studies are warranted to confirm our findings and to propose optimal use of medications in the management of rectal tenesmus.

Serotonin syndrome caused by interaction between fentanyl and amoxapine in a patient with cancer pain

<b>Objective</b>:To report a case of serotonin syndrome induced by an interaction between fentanyl and amoxapine in a patient treated for cancer pain. <b>Case:A</b> 37-year-old woman with recurrence of cervical cancer was treated with oxycodone and etodolac for her cancer pain in the gluteal region. She developed acute abdominal pain and received emergency surgery under the diagnosis of upper gastrointestinal tract perforation.Continuous fentanyl infusion was initiated during surgery and was continued postoperatively to control postsurgical and cancer pain. The route of fentanyl was changed to transdermal patch the next day, and dose was escalated during the following days in attempt to control her gluteal pain. Eight days after the operation, amoxapine was prescribed as an adjuvant analgesic. Five days later, the fentanyl dose was further escalated to 2100μg/day. The following day, the patient developed tremors of the extremities, confusion and hallucinations, followed by fever and involuntary movements of the lower extremities. Amoxapine was discontinued and the symptoms subsided within 4 days.<b>Conclusion</b>:Co-administration of a tricyclic antidepressant and high doses of fentanyl precipitated serotonin syndrome in this patient.